Cyclic loading

[julyan]

Hello everyone
I want to verify my modeling use of an experimental model.
How can I run an analysis cyclic loading?

[fmk]

transient or static analysis? though it deoes not really matter. you vary loads by using a Path time series in a load pattern.

[julyan]

Dear fmk,
thanks for your help.
i want to run a static analysis.

[MohsenShani]

$nodetag #define node for cyclice disp
$dof #use dof 1
constraints Plain
numberer Plain
system BandGeneral
test NormDispIncr 1.0e-8 60
algorithm Newton

set disploop [ list 0.0100 0.0200 0.0300 0.0400 0.0500 0.0600 0.0700 0.0800 0.0900 0.1000 0.1100 0.1200 0.1300 0.1400 0.1500 0.1600 0.1700 0.1800 0.1900 0.2000 0.2100 0.2200 0.2300 0.2400 0.2500 0.2600 0.2700 0.2800 0.2900 0.3000 0.3100 0.3200 0.3300 0.3400 0.3500 0.3600 0.3700 0.3800 0.3900 0.4000 0.4100 0.4200 0.4300 0.4400 0.4500 0.4600 0.4700 0.4800 0.4900 0.5000 0.5100 0.5200 0.5300 0.5400 0.5500 0.5600 0.5700 0.5800 0.5900 0.6000 0.6100 0.6200 0.6300 0.6400 0.6500 0.6600 0.6700 0.6800 0.6900 0.7000 0.7100 0.7200 0.7300 0.7400 0.7500 0.7600 0.7700 0.7800 0.7900 0.8000 0.8100 0.8200 0.8300 0.8400 0.8500 0.8600 0.8700 0.8800 0.8900 0.9000 0.9100 0.9200 0.9300 0.9400 0.9500 0.9600 0.9700 0.9800 0.9900 1.0000 1.0100 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.1 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.2 1.21 1.22 1.23 1.24 1.25 1.26 12.7 1.28 1.29 1.3 1.31 1.32 1.33 1.34 1.35]
for {set i 1} {$i<=[llength $disploop]} {incr i 1} {
set dispincr [expr -1.0*pow((-1.0),[expr $i-1])*[lindex $disploop [expr $i-1]]/$n]
integrator DisplacementControl $nodetag $dof $dispincr
analysis Static
analyze $n
}

puts "Cyclic Done!"

[julyan]

Dear MohsenShani,
Thanks for your guide, I used your code but could you explain about n parameter?

Best

[mgrubisic]

In the case of asymmetric displacement values under static reversed cyclic loading, it is possible to easily define a step value between the each peak displacement in a positive and negative direction, as follows:

...

set disploop [ list 0.0 0.1 -0.15 0.2 -0.24 ]; # etc, peak values of displacement in the positive and negative direction (start with zero!)

set n 5; # the number of steps between each peak displacement

for { set i 1 } { $i <= [ llength $disploop ] } { incr i 1 } {

set dispincr [expr [expr [lindex $disploop [expr $i]] - [lindex $disploop [expr $i-1]]] / $n];

puts "dispincr_$i $dispincr"

# integrator DisplacementControl $nodetag $dof $dispincr
# analysis Static
# analyze $n

}

puts "Cyclic Done!"

Thanks to MohsenShani!

[julyan]

Dear mgrubisic,
Thanks for your guide,And cyclic analysis (Displacement control) is needed to define a lateral load pattern or not?